n. (Zool.) Any insect of the genus Perla, or family Perlidæ. See Stone fly, under Stone. [ 1913 Webster ]
n. (Min.) Same as Pearlite. [ 1913 Webster ]
a. (Min.) Relating to or resembling perlite, or pearlstone; as, the perlitic structure of certain rocks. See Pearlite. [ 1913 Webster ]